Someone issue #2298 to cover this,
(http://gridengine.sunsource.net/issues/show_bug.cgi?id=2298)
But it seems that this hasn't been given a very high priority.
I think that this is a major defect. Array jobs dramatically increase
the scalability of the scheduler and they are also very convenient for
all my users.
Perhaps if more people are a little more vocal about this being an
important issue it will get more attention.
-----Original Message-----
From: Iwona Sakrejda [mailto:isakrejda at lbl.gov]
Sent: Wednesday, June 27, 2007 12:01 PM
To: users at gridengine.sunsource.net
Subject: Re: [GE users] CPU usage by array jobs
Has any of the experts looked at the following problem? I wonder if you
need more evedence and if yes of what kind? This problem is really
making
it impossible to get users stick with the array jobs....
Thanks a lot,
Iwona
Pascal Wassam wrote:
> I just conducted a test run.
>> My notes:
>> 4 nodes totaling to 7 cpus on all.q, each node has 4 slots in queue
> config.
> SGE 6.1. All jobs are identical, cpuburn, set to run for 5 minutes.
>> scheduler conf:
>> policy_hierarchy OS
> weight_tickets_share 100000
>> share tree:
>> id=0
> name=template
> type=0
> shares=0
> childnodes=1
> id=1
> name=default
> type=0
> shares=100
> childnodes=NONE
>> queue is disabled, and empty.
> 1000 individual jobs are queued as user pascal
> 1 array job of 1000 subjobs is queued as user ben
>> usage is cleared (qconf -clearusage)
>> at the starting line:
>> Queued per user:
> 1000 pascal qw
> 1000 ben qw
>> bang: qmod -e all.q
>> 1 minute in:
>> Running per user:
> 8 pascal r
> 8 ben r
> Queued per user:
> 992 pascal qw
> 992 ben qw
>> A while later:
>> Running per user:
> 10 pascal r
> 1 ben r
> Queued per user:
> 991 ben qw
> 973 pascal qw
>> And it continues this way:
>> Running per user:
> 8 pascal r
> 2 ben r
> Queued per user:
> 987 ben qw
> 952 pascal qw
>> -Pascal
>> Pascal Wassam wrote:
>> I would like to second all the experiences Iwona has written about
>> here. I will also attempt to conduct some tests and present something
>> that is repeatable for developers to play with.
>>>> -Pascal
>>>> Iwona Sakrejda wrote:
>>> Since this is a somehow different problem I gave it a new title.
>>>>>> Rayson Ho wrote:
>>>>> Another problem I am having is that array jobs seem to be
overcharged
>>>>> when the usage is calculated (could you point me to the section of
>>>>> code that
>>>>> deals with it/ I'll be happy to read it). Looks like each array
>>>>> job gets
>>>>> the CPU usage of the whole array. Array jobs are very helpful but
>>>>> users are
>>>>> fleeing from them in droves.....
>>>>>>>> How to reproduce it?? Is it a parallel or serial job??
>>> It happens to serial jobs. I have not done thorough studies yet, but
>>> I see that
>>> usage for owners of array jobs greatly exceeds what I estimate it
>>> should be.
>>>>>> Also when I clear usage, then only the usage from that moment should
be
>>> taken into account - right? And I see that a user who has an array
>>> jobs, gets
>>> right away usage that exceeds what he has running at that point.
>>>>>> Another shred of evidence is that when they switch from array jobs
to
>>> individual jobs, they get a throughput that they feel is consistent
>>> with their share.
>>> If they use arrays their throughput dives.
>>>>>> I'll try to come with a clean example with numbers. It is in 6.0u4
>>> so since
>>> I have to upgrade anyway I was postponing more studies hoping that
>>> the upgrade will
>>> fix the problem. On the other hand it might not and it really
>>> increases the load
>>> when instead of 1 array job with 1000 members I get 1000 jobs.....
>>>>>> And today I noticed that discussion about shares and CPU consumption
so
>>> I hoped the right expert might be watching and it would be easy for
>>> him to look at it...
>>>>>> Iwona
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